1. Field of the Invention
The invention relates to an apparatus for recording and/or playing back signals on and/or from a record carrier contained in a cassette hereinafter referred to as a cassette-recording apparatus, for example, a tape cassette recorder and/or player. Such apparatus comprises a deck plate; Two cassette-centering pins which are disposed perpendicular to the deck plate and are rigidly connected thereto at their bases, and which each have a substantially conical tip and a locally thickened portion near this tip which, when the cassette is in position on the apparatus, is located within the cassette while a portion of the centering pin located between the base and the tip thereof cooperates with a centering edge of an associated centering opening in the cassette, which opening corresponds to the associated centering pin; and resilient means for urging each centering pin and the centering edge of the respective centering opening in the cassette into engagement with one another.
2. Description of the Prior Art
It is known to give the centering pins the shape of a cylinder on which is coaxially disposed a cone with a base having a diameter greater than the diameter of the cylinder. The apex of the cone is rounded. The transition from the sloping side of the cone to the base thereof is also rounded. It is this transitional part of the cone which forms the locally thickened portion. In the cassette, centering openings are formed of such a size that they just fit the thickened portion with slight play. In the cassette-recording apparatus a leaf spring is provided which presses against the rear side of the cassette, so that as soon as the relevant cassette wall in which the centering openings are formed has passed the thickened portions of the centering pins, the leaf spring presses the centering edges of the centering openings against the cylindrical portions of the centering pins. When the cassette is removed the cassette wall again has to be moved over the thickened portions of the centering pins against the spring pressure, which requires a certain force, so that the centering pins in co-operation with said spring prevent the cassette from inadvertently springing out of position during use of the cassette-recording apparatus as shown, for example, in German Offenlegungsschrift No. 1,524,934.
An advantage of the use of this type of centering pin is that the cassette, in the inserted position, can make only very slight movements in a vertical direction because the cassette presses against the thickened portions of the centering pins; further no force is required which presses the cassette downwards to keep it in position. However, a drawback is that the cassette can be moved in the plane of engagement over a distance which in practice is approximately 0.7 mm. due to the difference in diameter between the cylindrical portion of the pin and the locally thickened portion, i.e., the rounded portion at the base of the cone.
For this reason completely cylindrical pins are sometimes used as shown, for example, in the aforementioned German Offenlegungsschrift No. 1,524,934. Owing to the absence of the locally thickened portion the pin as a whole may be slightly thicker, so that the play in the horizontal plane can be limited to approx. 0.17 millimeter. Furthermore, the cassette can be removed more easily from the pins. However, this means that during use of the cassette it must be kept in position by a force which is exerted perpendicularly to the plane of engagement. Consequently, the cassette-recording apparatus, in addition to having means for pressing the cassette against the pins in the plane of engagement, must also be provided with additional pressure means. These means have to be provided on a lid which covers the cassette during use. With conventional plastic lids the resulting reactive force on the lid gives rise to undesired distortion.